Madhav Paudel

How to add ssh and gpg keys in GitHub or GitLab?

Tue, 13 May 2025 01:27:00 -0545

Configure git

Initial configuration of git if you have not set yet.

git config --global color.ui true
git config --global user.name "YOUR NAME"
git config --global user.email "YOUR@EMAIL.com"

Adding SSH key

Run this command in your terminal to generate new ssh key

ssh-keygen -t ed25519 -C "YOUR@EMAIL.com"

# Use this if your system doesn't support the Ed25519
ssh-keygen -t rsa -b 4096 -C "YOUR@EMAIL.com"

The next step is to take the newly generated SSH key and add it to your Github or GitLab account. You can add SSH key in your setting of GitLab or GitHub. You want to copy and paste the output of the following command and paste it in your ssh key setting.

# For ed25519
cat ~/.ssh/id_ed25519.pub

# For RSA
cat ~/.ssh/id_rsa.pub

Once you’ve done this, you can check and see if it worked:

# For GitHub
ssh -T git@github.com

# OR for GitLab
ssh -T git@gitlab.com

You will get a message like this

# For GitHub
Hi <your_usename>! You've successfully authenticated, but GitHub does not provide shell access.

# OR for GitLab
Welcome to GitLab, @<your_username>!

Signing commits with GPG

GitHub or GitLab can show whether a commit is verified or not when signed with a GPG key. All you need to do is upload the public GPG key in your profile settings.

Generating a GPG key

If you don’t already have a GPG key, the following steps will help you get started:

Install GPG for your operating system. If your Operating System has gpg2 installed, replace gpg with gpg2 in the following commands.
Generate the private/public key pair with the following command, which will spawn a series of questions:
```
gpg --full-gen-key
```

The first question is which algorithm can be used. Select the kind you want or press Enter to choose the default ECC (sign and encrypt): Please select what kind of key you want:

Please select what kind of key you want:
(1) RSA and RSA
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
(9) ECC (sign and encrypt) *default*
  (10) ECC (sign only)
  (14) Existing key from card
Your selection? 9

The next question is which elliptic curve you want. We recommend to go with the default one. Select the kind you want or press Enter

Please select which elliptic curve you want:
(1) Curve 25519 *default*
(4) NIST P-384
(6) Brainpool P-256
Your selection? 1

Next, you need to specify the validity period of your key. This is something subjective, and you can use the default value which is to never expire:

Please specify how long the key should be valid.
      0 = key does not expire
   <n>  = key expires in n days
   <n>w = key expires in n weeks
   <n>m = key expires in n months
   <n>y = key expires in n years
Key is valid for? (0) 0
Key does not expire at all

Confirm that the answers you gave were correct by typing y:
```
Is this correct? (y/N) y
```

Enter you real name, the email address to be associated with this key (should match a verified email address you use in GitLab) and an optional comment (press Enter to skip):

GnuPG needs to construct a user ID to identify your key.
Real name: Mr. Robot
Email address: <your_email>
Comment:
You selected this USER-ID:
"Mr. Robot <your_email>"
Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O

Pick a strong password when asked and type it twice to confirm.
Use the following command to list the private GPG key you just created:
```
gpg --list-secret-keys --keyid-format LONG <your_email>
```
Replace <your_email> with the email address you entered above.

Copy the GPG key ID that starts with sec. In the following example, that’s 5C426E801C00183B:

sec   ed25519/5C426E801C00183B 2025-05-13 [SC]
  1CFD5B42CF473B60466B69325C426E801C00183B
uid                 [ultimate] Mr. Robot <your_email>
ssb   cv25519/B3ED6E8715E10A6E 2025-05-13 [E]

Export the public key of that ID (replace your key ID from the previous step):
```
gpg --armor --export 5C426E801C00183B
```
Finally, copy the public key and add it in your profile settings

Associating your GPG key with Git

After you have created your GPG key and added it to your account, it’s time to tell Git which key to use.

Use the following command to list the private GPG key you just created:
```
gpg --list-secret-keys --keyid-format LONG <your_email>
```
Replace <your_email> with the email address you entered above.

Copy the GPG key ID that starts with sec. In the following example, that’s 5C426E801C00183B:

sec   ed25519/5C426E801C00183B 2025-05-13 [SC]
   1CFD5B42CF473B60466B69325C426E801C00183B
uid                 [ultimate] Mr. Robot <your_email>
ssb   cv25519/B3ED6E8715E10A6E 2025-05-13 [E]

Tell Git to use that key to sign the commits:
```
git config --global user.signingkey 5C426E801C00183B
```
Replace 5C426E801C00183B with your GPG key ID.

Signing commits

After you have created your GPG key and added it to your account, you can start signing your commits:

Commit like you used to, the only difference is the addition of the -S flag:
```
git commit -S -m "My commit msg"
```
Enter the passphrase of your GPG key when asked.
Push to GitLab and check that your commits are verified.

If you don’t want to type the -S flag every time you commit, you can tell Git to sign your commits automatically:

git config --global commit.gpgsign true

Verifying commits

Within a project or merge request, navigate to the Commits tab. Signed commits will show a badge containing either “Verified” or “Unverified”, depending on the verification status of the GPG signature.

Troubleshooting

run gpg --version, and make sure you have GnuPG version 2+ (not version 1) installed
run echo "test" | gpg --clearsign, to make sure gpg itself is working

If you get an error message saying “Inappropriate ioctl for device”, do this:

run export GPG_TTY=$(tty) and/or add that to your ~/.bashrc or ˜/.bash_profile

Referece Links

Starting docker in rails 7.1 with a separate MySQL container

Thu, 29 Feb 2024 02:00:28 -0545

Setting Up MySQL

Pull the MySQL image:
```
docker pull mysql/mysql-server
```
Run the MySQL container:
```
docker run -it -d \
  --name=mysql_container \
  -p 3307:3306 \
  -e MYSQL_ROOT_PASSWORD=password \
  -e MYSQL_ROOT_HOST=% \
  mysql/mysql-server \
  --default-authentication-plugin=mysql_native_password
```
- Explanation:
  - -it: Run in interactive.
  - -d: Run the container in the background.
  - –name=mysql_container: Name the container for easier management.
  - -p 3307:3306: Map the container port 3306 (MySQL) to host port 3307.
  - -e MYSQL_ROOT_PASSWORD=password: Set the root password for the MySQL user.
  - -e MYSQL_ROOT_HOST=%: Allow connections from any host.
  - –default-authentication-plugin=mysql_native_password: Use the traditional password authentication plugin.
Get the container’s IP Address:
```
docker inspect mysql_container | grep IPAddress
```
This will display the container’s IP address, which will be used later.
Set environment variables:
```
export DATABASE_URL='mysql2://root:password@<container_ip>/<db_name>:3306?encoding=utf8mb4'
export RAILS_MASTER_KEY=<rails_master_key>
```
- Replace <container_ip> with the IP address obtained in the previous step.
- Replace <db_name> with the name of the database you want to use.
- Replace <rails_master_key> with the master key from config/master.key.

Running project

Build the project image:
```
docker-compose build -t <rails_app> .
```
- Replace <rails_app> with the name you want to give to the image.
- This will build the image using the Dockerfile.
Run the project container:
```
docker run --rm -it -p 3000:3000 --name=<rails_app_container> \
  -e DATABASE_URL=$DATABASE_URL \
  -e RAILS_MASTER_KEY=$RAILS_MASTER_KEY \
  <rails_app>
```
- Replace <rails_app_container> with the name you want to give to the container.
- Replace <rails_app> with the name of the image you built in the previous step.
- Explanation:
  - –rm: Remove the container when it stops.
  - -it: Run in interactive.
  - -p 3000:3000: Map the container port 3000 (Rails) to host port 3000.
  - -e DATABASE_URL=$DATABASE_URL: Set the database URL environment variable.
  - -e RAILS_MASTER_KEY=$RAILS_MASTER_KEY: Set the Rails master key environment variable.

Debugging

View MySQL container logs:
```
docker logs mysql_container
```
Enter the MySQL container:
```
docker exec -it mysql_container bash
```
- This will open a bash shell inside the container.
- You can then run mysql -u root -p to enter the MySQL command line.
- Use exit to leave the container.

Controlling the MySQL container

Stop the container:
```
  docker stop mysql_container
```
Start the container:
```
  docker start mysql_container
```
Remove the container:
```
  docker rm mysql_container
```

Install ruby with rbenv and ruby-build

Thu, 30 Mar 2023 22:44:28 -0545

To install Ruby using ruby-build and rbenv, you can follow these steps:

Step 1

First, make sure you have ruby-build and rbenv installed on your system. You can check if you have them installed by running the following commands in your terminal:

which ruby-build
which rbenv

If either of these commands returns a path, it means that the corresponding tool is already installed on your system. If not, you can follow the installation instructions for your operating system.

Step 2

Next, check if the version of Ruby you want to install is available in ruby-build. You can do this by running the following command:

ruby-build --definitions | grep <version>

Replace <version> with the version of Ruby you want to install. If the version is available in ruby-build, you can proceed to step 3. Otherwise, you will need to wait for the update to become available in ruby-build, or you can try installing Ruby manually.

Step 3

Install the Ruby version using rbenv and ruby-build:

rbenv install <version>

Replace <version> with the version of Ruby you want to install. This will download the Ruby source code and compile it, which may take some time.

Step 4

Once the installation is complete, you can set the global version of Ruby to use:

rbenv global <version>

This will set the global version of Ruby to the version you just installed.

Step 5

Finally, verify that Ruby was installed correctly by running the following command:

ruby -v

This should display the version of Ruby you just installed.

If the version of Ruby you want to install is not available in ruby-build yet, but it is available in the official release, you can download the source code from the Ruby website and compile it manually. Once you have the source code, you can use ruby-build to compile and install it:

Step 1

Download the Ruby source code from the official Ruby website: https://www.ruby-lang.org/en/downloads

Step 2

Extract the source code to a directory of your choice.

Step 3

Use ruby-build to compile and install the Ruby version:

ruby-build <path/to/source/code> <install/path>

Replace <path/to/source/code> with the path to the directory containing the extracted source code, and <install/path> with the path where you want to install Ruby.

Step 4

Once the installation is complete, you can set the global version of Ruby to use:

rbenv global <version>

Step 5

Replace <version> with the version of Ruby you just installed.

Finally, verify that Ruby was installed correctly by running the following command:

ruby -v

This should display the version of Ruby you just installed.

B.Sc. CSIT Sixth Semester All Questions 2075

Tue, 29 Jan 2019 08:38:47 -0545

Here is a collection of all subjects of B.Sc.CSIT sixth semester questions 2075. Click the respective subject to view or download the question.

Compulsory Subjects

Software Engineering (CSc.351)
Compiler Design and Construction (CSc.352)
Web Technologies (CSc.353)
Real Time Systems (CSc.354)

Alternative Subjects

Fundamental of E-commerce (CSc.356)
Net Centric Computing (CSc.360)
Embedded System Programming (CSc.362)
Image Processing (CSc.363)

C++ program of transfering balance from one account to another

Fri, 20 Jul 2018 01:49:47 -0545

Simple Network Design With DNS Servers in Packet Tracer

Sun, 18 Mar 2018 01:00:31 -0545

fig. Simple network with DNS and FTP server

We should use copper cross-over cable(dotted lines) to connect from router to router and copper straight-through cable(smooth line) to connect from router to switch and switch to end devices.

Here we are assuming the ip addresses as given in the figure above.

IP configuration:

We are configuring all the static ip. An example for PC0 is given in the figure below.

PC0
IP address: 192.168.1.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1
DNS Server: 192.168.5.4

fig. IP configuration for PC0

In the same way, you can configure IP of all end devices as:

PC1
IP address: 192.168.1.3
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1
DNS Server: 192.168.5.4

PC2
IP address: 192.168.5.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.5.1
DNS Server: 192.168.5.4

Web and FTP server
IP address: 192.168.5.3
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.5.1

DNS Server
IP address: 192.168.5.4
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.5.1

Make sure that we have not write DNS server to the Web, FTP and DNS server.

For Router

Router0 To Switch0
Ip address: 192.168.1.1
Subnet Mask: 255.255.255.0
fig. An example figure for IP configuration of Router0 To Switch0

Router0 To Router1
Ip address: 192.168.50.1
Subnet Mask: 255.255.255.0

Router1 To Switch1
Ip address: 192.168.5.1
Subnet Mask: 255.255.255.0

Router1 To Router0
Ip address: 192.168.50.2
Subnet Mask: 255.255.255.0

For the network to communicate for different network, we have to set static routes at router. We can do that by clicking on the router and from the config option select static, and then configure as follows:

Static Route for Router0
Network: 192.168.5.0
Mask: 255.255.255.0
Next Hop: 192.168.50.2
And then click Add fig. Static Routes for Router0

Static Route for Router1
Network: 192.168.1.0
Mask: 255.255.255.0
Next Hop: 192.168.50.1
And then click Add

Now our network is complete. It’s time to test and enjoy.

DNS

Let us check if web server is pinging to PC1 or not. Go to terminal of PC1 and type ping 192.168.5.3

fig. Pinging web server from PC0

Let us check the files at web server. When we click web server and click services, we see that:

fig. Web Server files

Now, browse it from PC0. Click on PC0 and browse https://192.168.5.3, you will get the page like following:

fig. Web browing from PC0 using IP address

If we want to browse files using custom domain. We have to configure custom domain to point to web server at DNS server. Here, I am using www.madhav.com (You can use your desired domain) To do that follow the steps below:

Click on DNS server
Click DNS from the services option
Turn on DNS Service
On Resource Records:- Name: www.madhav.com, Type: A Record, Address: 192.168.5.3

fig. DNS Configuration

Now, browse http://www.madhav.com, your site is now working.

fig. Web browing from PC0 using custom domain

FTP

We have same server for FTP and DNS. To make ftp server, first make sure it is turned on. And then we need password to login ftp server. Default username is cisco and password is also cisco

fig. FTP server

FTP GET

Now, extract the files from ftp server to PC0. Go to terminal of PC0 and login to ftp server:

ftp 192.168.5.3
username: cisco
password: cisco

fig. FTP login

You can get the files of ftp using get <filename> fig. FTP GET

FPT PUT

This means saving our files from computer to ftp server. We do this by using the command put <filename>

First, create a file going to PC0, I named it as madhav.txt

fig. Creating file in PC

Finally, put the file to server put madhav.txt fig. FTP PUT

C program to find the HCF of the two numbers

Sun, 25 Dec 2016 01:49:47 -0545

#include<stdio.h>
#include<conio.h>
int hcfactor(int x,int y)
{
	if(y==0)
	return x;
	else
	return hcfactor(y,x%y);
}
void main()
{
	int a,b,f;
	printf("Enter two numbers:\n");
	scanf("%d%d",&a,&b);
	f=hcfactor(a,b);
	printf("HCF of %d and %d is %d.",a,b,f);
	getch();
}

C++ program of file handling to write a file in the disk and read from a file

Sun, 25 Dec 2016 01:49:47 -0545

#include<iostream.h>
#include<conio.h>
#include<fstream.h>
int main()
{
	int roll;
	char name[20];	
	ofstream outf("madhav.txt");	//creates a file madhav.txt
	cout<<"Enter name:";
	cin>>name;
	cout<<"Enter Roll No:";
	cin>>roll;
	outf<<"Name = "<<name;
	outf<<"\nRoll No. = "<<roll;
	outf<<endl;
	cout<<"\nData successfully written to disk.\n";
	outf.close();
	
	const int LEN = 80;
	char text[LEN];
	ifstream infile("madhav.txt");	//file is opened for read operation
	cout<<"\nThe data reading from file is:\n";
	while(infile)
	{
		infile.getline(text,LEN);
		cout<<endl<<text;
	}
	infile.close();
	
	getch();
	return 0;
}

Stopping by Woods on a Snowy Evening

Thu, 22 Dec 2016 02:50:47 -0545

-BY ROBORT FROST

Whose woods these are I think I know.
His house is in the village though;
He will not see me stopping here
To watch his woods fill up with snow.

My little horse most think it queer
To stop without a farmhouse near
Between the woods and frozen lake
The darkest evening of the year.

He gives his harness bells a shake
To aske if there is some mistake.
The only other sound's the sweep
Of easy wind and downly flags

The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.

Welcome to Madhav's Blog!

Wed, 21 Dec 2016 06:18:24 -0545

You are welcome to my site!

This is the personal blog for posting my ideas and views.